1. Field of the Invention
The present invention generally relates to a wobble plate type refrigerant compressor and, more particularly, to a thrust ball supporting mechanism for a wobble plate type compressor.
2. Description of the Prior Art
A thrust support mechanism of the wobble plate type refrigerant compressor is well known. For example, U.S. Pat. No. 4,870,893 to Takahashi discloses a refrigerant compressor wherein the rotation of the compressor drive shaft is converted into reciprocating motion through a cam rotor. The cam rotor has a sloping end surface and is mounted on an end of the drive shaft. A wobble plate bears against the cam rotor through needle bearings, and is supported on a fixed member such as a cylinder block in such a manner that the wobble plate nutates, but does not rotate. Thus, the rotation of the cam rotor causes wobble plate to nutate, and the piston rods connected to the wobble plate are reciprocated to compress fluid within the cylinders.
In a known wobble plate supporting mechanism, a bevel gear is fixed to the wobble plate at the center thereof and another bevel gear is fixedly supported on the cylinder block. The bevel gears mesh so that the bevel gear on the wobble plate is prevented from rotating. Both of the bevel gears have ball seats at their center in which a bearing ball sits. Thus, while the bevel gear on the wobble :plate is prevented from rotating, it nutates along the ball surface.
The bearing ball and ball seats on the bevel gears are subjected to some of the largest axial loads in the compressor. Accordingly, proper lubrication of these parts is imperative. Under normal operating conditions, they are lubricated by a mist of lubricating oil generated by the moving parts the compressor. However, in the event that the compressor suffers a leakage of lubricating oil or continues to operate when the level of lubricating oil has decreased below a threshold level, the engaging surfaces may not be sufficiently lubricated, possibly resulting in abrading of the bearing ball or even failure of the compressor.
In addition, prior art bevel gear rotation prevention mechanisms are substantially rigid bodies. The metal to metal contact of the bevel gears has been known to cause considerable and undesirable noise and vibration. This in turn can reduce the marketability and effective life of the compressor.
It is these and other shortcomings of prior art wobble plate support mechanisms that the preferred embodiment seeks to address.